Vibrational corrections to linear and nonlinear static electric properties of polyatomic molecules at non-optimum reference geometry

Abstract

We show how vibrational contributions to the static electric properties of polyatomic molecules may be computed with respect to arbitrary reference geometries. The derived geometry corrective term that compensates for the effect of using a non-optimum geometry, is a simple function of the energy gradient and first-order nuclear derivative of the electric property, summed over the number of normal vibrational modes of the molecule. We illustrate the possible orders of magnitude of the geometry correction for the major electric properties of the water molecule, computed at different levels of electronic structure theory: SCF, MP2, CCSD and CCSD(T).